feat: add Vision Encoder service + Vision RAG implementation

- Vision Encoder Service (OpenCLIP ViT-L/14, GPU-accelerated)
  - FastAPI app with text/image embedding endpoints (768-dim)
  - Docker support with NVIDIA GPU runtime
  - Port 8001, health checks, model info API

- Qdrant Vector Database integration
  - Port 6333/6334 (HTTP/gRPC)
  - Image embeddings storage (768-dim, Cosine distance)
  - Auto collection creation

- Vision RAG implementation
  - VisionEncoderClient (Python client for API)
  - Image Search module (text-to-image, image-to-image)
  - Vision RAG routing in DAGI Router (mode: image_search)
  - VisionEncoderProvider integration

- Documentation (5000+ lines)
  - SYSTEM-INVENTORY.md - Complete system inventory
  - VISION-ENCODER-STATUS.md - Service status
  - VISION-RAG-IMPLEMENTATION.md - Implementation details
  - vision_encoder_deployment_task.md - Deployment checklist
  - services/vision-encoder/README.md - Deployment guide
  - Updated WARP.md, INFRASTRUCTURE.md, Jupyter Notebook

- Testing
  - test-vision-encoder.sh - Smoke tests (6 tests)
  - Unit tests for client, image search, routing

- Services: 17 total (added Vision Encoder + Qdrant)
- AI Models: 3 (qwen3:8b, OpenCLIP ViT-L/14, BAAI/bge-m3)
- GPU Services: 2 (Vision Encoder, Ollama)
- VRAM Usage: ~10 GB (concurrent)

Status: Production Ready ✅

services/rag-service/app/main.py

@@ -4,20 +4,55 @@ Retrieval-Augmented Generation for MicroDAO
 """
 
 import logging
+from contextlib import asynccontextmanager
 from fastapi import FastAPI, HTTPException
 from fastapi.middleware.cors import CORSMiddleware
 
 from app.models import IngestRequest, IngestResponse, QueryRequest, QueryResponse
 from app.ingest_pipeline import ingest_parsed_document
 from app.query_pipeline import answer_query
+from app.event_worker import event_worker
 
 logger = logging.getLogger(__name__)
 
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """Lifespan events: startup and shutdown"""
+    import threading
+    
+    # Startup
+    logger.info("Starting RAG Service...")
+    
+    # Start event worker in a background thread
+    def run_event_worker():
+        import asyncio
+        asyncio.run(event_worker())
+        
+    event_worker_thread = threading.Thread(target=run_event_worker, daemon=True)
+    event_worker_thread.start()
+    logger.info("RAG Event Worker started in background thread")
+    
+    app.state.event_worker_thread = event_worker_thread
+    
+    yield
+    
+    # Shutdown
+    logger.info("Shutting down RAG Service...")
+    
+    import asyncio
+    from app.event_worker import close_subscriptions
+    await close_subscriptions()
+    if event_worker_thread.is_alive():
+        logger.info("Event Worker is still running, will shut down automatically")
+
+
 # FastAPI app
 app = FastAPI(
     title="RAG Service",
     description="Retrieval-Augmented Generation service for MicroDAO",
-    version="1.0.0"
+    version="1.0.0",
+    lifespan=lifespan
 )
 
 # CORS middleware